I had been using ANA and Aeroplan but gave up on them as they are sooooooo slow.
Now I use
AwardTravelr - Searching across all possibilities to make your frequent flyer miles work for you, as it is easy and quick and showed the same availability as the other two. (I searched by sector)
Yes, all flights were available when I phoned US Airways and it was quite easy just quoting dates and flight numbers. The operator seemed quite surprised that I knew the availability of each flight.
I should have booked the previous week instead of procrastinating though, as J disappeared on the CDG-VIE sector and LH J was available from FRA-BOS which I would have preferred over UA to ORD. (We're ducking down to SJU for 5 nights and the AA YUP fares are cheaper from BOS). Oh, well, you live and learn